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AC
| Question | Answer |
|---|---|
| A liquid line filter drier should be placed between the | condenser and the metering device |
| A temperature differential across a filter drier indicates | restricted filter drier |
| a liquid receiver is used to | store liquid refrigerant |
| an accumulator is used to | prevent liquid refrigerant from reaching the compressor |
| a sight glass would normally be located | in the liquid line before the metering device |
| bubbles in a sight glass could be an indication of | refrigerant blend with a high temperature glide |
| A liquid to suction heat exchanger is often used to | increase liquid sub cooling |
| the oil pressure safety switch is operated by | the difference between crankcase pressure and oil pressure |
| a low pressure cut off switch is used to | establish a minimum operating pressure in the evaporator |
| an energy recovery ventilator is | an air to air heat exchanger to recover heat |
| which of the following is true of a solenoid valve in a pump down system | it is located before the metering device |
| heat which causes a change in temperature of a substance is called | sensible heat |
| heat added to a substance without a rise in temperature | latent heat of vaporization |
| heat added to the refrigerant in a vapor state after the evaporation process is called | superheat |
| the movement of heat by way of fluid or air is called | convection |
| the movement of heat by direct contact is called | conduction |
| zero psia is | a pressure which cannot be further reduced |
| zero psig is | the same as atmospheric pressure |
| the temperature at which moisture will start to condense from the air is called | dew point temperature |
| what is the recommended residential indoor relative humidity for summer | 50% |
| water will vaporize at what temperature in a 28 in hg vacuum | 100 degrees F |
| the standard unit for measuring the quantity of heat in a substance is | the British thermal unit BTU |
| which of the following symptoms would be indicative of an oil logged condenser | high discharge line pressure and low liquid line pressure |
| a partially iced over evaporator can be caused by | an undercharge |
| can be used for leak detection with all high pressure refrigerants | soap bubble solution |
| when using an electronic leak detector the sensor probe | should be moved at approximately 1 inch for every 2 seconds |
| moisture in a refrigeration system can cause | compressor failure |
| in order to remove as much moisture as possible from a system | triple evacuate the system to 500 microns with a deep vacuum pump |
| an overcharge of refrigerant will cause | increased head pressure |
| A customer complains that their air conditioning system is running constantly, but not cooling enough. the suction line is very cold and the compressor is sweating the most likely cause is | a restriction of the return air or a dirty evaporator |
| compressor was replaced unit is not cooling properly when you arrive and inspect the unit you find that evaporator seems to be starved for refrigerant on examining the condensing unit you find that the liquid line is sweating where it leaves the drier | Debris from the burned out compressor has clogged the drier |
| an inefficient compressor is usually indicated by BLANK head pressure and Blank suction pressure | lower the than normal/ higher than normal |
| what is not a symptom of a hermetic system that is low on refrigerant | high head pressure |
| frost on the suction line indicates | that its temperature is below the dew point and below 32 degrees F |
| when a TEV or a capillary tube is used as a metering device a low refrigerant charge will cause | low head pressure |
| solid contaminants such as sludge and carbon from a sever hermetic compressor motor burn out are best removed | by installing filter driers in both the liquid and suction lines |
| no cooling complaint unit to be completely out of refrigerant technician decides to use a trace amout of refrigerant and BLANK in order to pressurize the system | an inert gas |
| system is started the compressor is noisy and running hot the most probable cause of the noise is | low oil in the system |
| low operating pressures and low system amp draw this could be an indication of | A low airflow across the evaporator |
| air or other non condensable gasses in a capillary tube air conditioning system will cause these sysmptoms | low suction pressure and high discharge pressure |
| A refrigerant overcharge in a capillary tube air conditioning system will cause these symptoms | high suction pressure and high discharge pressure |
| a compressor that has a broken valve will cause these symptoms | high suction pressure and low discharge pressure |
| a low refrigerant charge in an air conditioning system will cause these symptoms | low suction pressure and low discharge pressure |
| a faulty condenser fan motor on an air conditioning system will cause these sysmptoms | high suction pressure and high discharge pressure |
| a dirty evaporator in AC systme will cause these sysmptoms | low suction pressure and low discharge pressure |
Created by:
nelrod